Liquid storage tank venting device for zero gravity environment



1967 s. s. PAPELL ETAL 3,295,545

LIQUID STORAGE TANK VENTING DEVICE FOR ZERO GRAVITY ENVIRONMENT Filed Dec. 13, 1963 {III/III: IYIIIIIIIIIII 1 I/IIII/I/I/I/IIAYIIII/ 0000 use Bnncc III/llIYIIIIIIIIIIII/IIIIII r oouauouooucuu VIIIIIIAVIIIA INVENTORS SOLOMON $.PAPELL ROBERT w. GRAHAM K149i; W 7M ATTORNEYS United States Patent 3,295,545 LIQUID STORAGE TANK VENTING DEVICE FOR ZERO GRAVITY ENVIRONMENT Solomon Stephen Papell, Berea, and Robert W. Graham, Parkv ew, Ohio, assignors to the United States of America as represented by the Administrator of the National Aeronautics and Space Administration Filed Dec. 13, 1963, Ser. No. 330,209 1 Claim. (Cl. 137197) The invention described herein may be manufactured and used by or for the Government of the United States without the payment of any royalties thereon or therefor.

The present invention relates, generally, to a venting device and, more particularly, to a zero-gravity venting device for vessels or tanks storing magnetic fluids such as those disclosed in co-pending application Serial No. 315,096 filed October 9, 1963 now Patent No. 3,215,572, issued November 2, 1965, and having a common assignee.

Under the zero-gravity environment of outer space, fluids such as cryogenic fluids or liquid propellants become disoriented with the result that, the liquid and vaporous phases of the fluid are free to disperse and intermix throughout the storage tank. From this condition ensues the problem of proper tank venting since radiant heat gain to the storage tank from space causes a dangerous pressure build-up within the tank which must be compensated for in order to prevent tank rupture and to insure that pump inlet pressures are within design limitations so that pumping may be successfully carried out. Of course, the storage tank or pump could be built with thickened containing walls and heavier moving parts, but the excessive weight caused thereby would engender a large energy penalty, necessitating heavier and more cumbersome lower stage boosters or lowered payload. A more advantageous solution to this problem would seem to be the use of a tank venting device to bleed off excess pressure. However, since the gaseous and liquid phases of fluid are intermixed, the use of normal venting devices would result in the loss of large amounts of usable liquid.

Accordingly, it is an object of the invention to provide a venting device which is operative under zero-gravity conditions.

It is another object of the invention to provide a venting device which orients the fluid by magnetic force.

It is still another object of the invention to provide a venting device which selectively vents only the gaseous phase of fluid from the storage tank.

It is yet another object of the invention to provide a venting device for use with a magnetic propellant such as disclosed in the aforementioned co-pending application.

A more complete appreciation of the invention and many attendant advantages thereof will be more readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein like numerals are used to identify like parts in both embodiments.

In the drawings:

FIG. 1 is an elevation view in section of one embodiment of the invention showing the vent port closed.

FIG. 2 is a view of the venting device of FIG. 1 in larger scale showing the vent port open.

FIG. 3 is an elevation view partly in cross section of an alternate embodiment of the invention showing the vent port in closed position.

FIG. 4 is a view of the venting device of FIG. 3 with the vent port open.

According to the present invention, the foregoing and other objects are obtained by providing a novel venting from the remainder of the vent pipe closes Patented Jan. 3, 1967 device for a fluid storage means in which the liquid and vaporous phases of the fluid are selectively separated and the gaseous phase vented to space. A magnet is utilized to orient and separate the two phases of the fluid while a movable valve element mounted in the venting device permits the separated vaporous phase to exhaust to space. Additionally, a pressure sensitive means is provided to control operation of the valve element. In a further refinement of the invention, the movable valve element is solenoid operated and is disposed as to clear the venting device of entrained liquid, returning it to the storage tank by a piston-like motion. In this embodiment a timing means is also provided to regulate the time sequencing operation of the solenoid.

Referring now to the drawings, where throughout like numerals are used to indicate like elements, there is shown in FIGS. 1 and 2 one embodiment of the invention wherein a tank and venting assembly 10 is provided with a storage tank 12 in which the liquidous phase 14 and gaseous phase 16 of the fluid 17 are stored. Because of the absence of any gravitational force on these phases, they are randomly dispersed and intermixed throughout the tank 12 (as best seen in FIG. 1). Venting device 18, fixed to the tank, provides an exit flow passageway from the tank interior 20 to control excess pressure build-up caused by the boil-off of the stored fluid.

This venting device is sealingly attached to tank wall 22 by welding or the like to insure that there is no unwanted leakage of the stored fluid to space, and is formed from a pipe 24 having an inner portion 26, an intermediate port portion 28, and an end portion 32. The inner portion 26 of the vent pipe 24 extends into the tank interior 20 and is open thereto to provide communication for the gaseous phase of the fluid to the venting device, while the ports 30 in the intermediate portion 28 are capable of being alternately opened and closed by valve element 36 to permit exhaust of this vaporous phase to space. End portion 32 made integral or separate the end of the pipe 24 to seal the tank and venting assembly from space. Attached between the end portion 32 and the valve element 36 is compressed spring 34, this spring being preloaded to resist a selected pressure safely with the design limitations of the tank 12. On the inner portion 26 of the vent pipe 24, magnet 38 is mounted so as to surround the vent pipe and trap the magnetized liquid and prevent its escape to space.

In operation, as boil-off of the fluid progresses, pressure increases in tank 12 forcing the valve element 36 against the preloaded spring 34. As the spring compresses, the valve element 36, within the vent pipe 24, moves away from sealing engagement with ports 30 towards the end portion 32 to thereby permit the gaseous phase 16 of the fluid to escape from the tank in suflicient amounts to permit the valve element to again seal the ports 30. As set out in the aforementioned co-pending applications, the liquidous phase of the fluid 17 has colloidally suspended therein metal particles having magnetic properties. Magnet 38 attracts and holds this liquidous phase to form a slug which by a process of adhesion or surface tension remains held adjacent to the magnet while the non-magnetic gaseous phase bubbles through the slug and passes out the exit ports.

Referring now to the embodiment of the invention illustrated in FIGS. 3 and 4, wherein the venting device includes a valve element having solenoid actuation.

The tank and vent assembly, indicated generally by the numeral 40, is provided with a venting device 42, similar in many respects to the venting device of the first embodiment. It includes a vent pipe 44 having an inner portion 46 in sealing communication with the tank interior 20 and port and end portions 48, 50, respectively, extending outwardly from the tank 12. The vent portion 48, similarly to the first embodiment, is provided with ports 30 through which the gaseous phase of the fluid exhausts to atmosphere.

End portion 50 made either integral or separate from the remainder of the vent pipe seals the end of the pipe and provides one of the connections for a spring 52. The opposite end of this spring is connected to a valve element 60 and is always under slight compression so as to urge the valve element into sealing engagement with the ports 30. A pressure tap 54 which is sealingly afiixed to the tank 12 at one end, adjacent to the vent pipe 44, has its opposite end connected to a pressure transducer 56 set for a predetermined pressure safely within the design limitations of the tank 12. Leads 57 provide connection to an outside power source (not shown) while leads 58 connect the transducer 56 to a timer 59, for example, a time delay relay, which actuates the valve element 60 through solenoid 62 having windings 64. The timer 59 holds the valve element open a predetermined time to permit exhaust of the gaseous propellant 16 and to prevent too rapid sequencing of the valve element and then switches off the solenoid to permit the valve element 60 to return to the closed position illustrated in FIG. 3. As can be easily seen in this figure, this position of the valve element 60 discharges any liquid phase 14 of the magnetic fluid back into the tank to prevent a large build-up of liquid in the venting device itself.

The operation of this embodiment of the invention is similar to that of the embodiment illustrated in FIGS. 1 and 2 but, because of the positive solenoid actuation and consequent purging of the venting device by the valve element, provides somewhat better control over extended periods of operation.

It is clear from the foregoing that the present invention may be etfectively utilized for venting any stored magnetic fluid, and that, obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is to be understood, therefore, that within the scope of the appended claims, the invention may be practiced other than as specifically described.

What is claimed is:

A venting device for use with a storage tank adapted I tank in sealing communication therewith, said vent pipe having an inner portion extending into said tank and outer portion disposed outwardly of said tank, said inner portion having an open end and said outer portion having a. closed end; port means in said outer portion of said vent pipe; magnetic means disposed around said inner portion of said vent pipe to prevent passage of the liquid phase of said magnetic fluid from said tank to said port means; a plunger-like valve element slidably disposed in said vent pipe and having suflicient travel so that the end of said valve means facing the interior of said tank can move between a point inward of said magnetic means and a point outward of said port means; a preloaded spring means disposed between said valve element and said closed end of said outer portion of said vent pipe, said valve means compressing said spring means to unblock said port means thereby venting a portion of the gas phase of said magnetic fluid when pressure in said tank exceeds a predetermined magnitude, said spring means biasing said valve means to a position at which the end of said valve means facing said interior of said tank is normally positioned inwardly of said magnetic'rneans whereby after each venting action, said valve means forces magnetic liquid from said vent pipe into said tank thereby preventing a build-up of magnetic liquid in said vent pipe.

References Cited by the Examiner UNITED STATES PATENTS 1,553,737 9/1925 Allingham -3 2,305,519 12/1942 Dunmire 137-538 2,556,906 6/1951 Del Mar 137487.5 XR 2,575,906 11/1951 Bullard 25165 XR FOREIGN PATENTS 561,861 4/1957 Italy.

ALAN COHAN, Primary Examiner. WILLIAM F. ODEA, Assistant Examiner. 

